The invention refers to the devices for the quality and/or quantity testing, and/or the levelling of cigarettes or any other rod-like articles, particularly in the tobacco processing industry, such as cigarette filter rods, or the like.
The invention refers particularly to the quality and/or quantity testing, and/or the levelling devices of the aforementioned kind, comprising one or more feeler pins set in a substantially co-axial relation with the cigarette or cigarettes to be controlled or to be levelled, and being moved from a retracted rest position axially toward the respective cigarette or cigarettes, so as to be caused to contact the ends thereof, whereby they apply thereon an elastic pressure, such as to shift the cigarette or the cigarettes against a suitable abutment for aligning same, and/or they signal their presence or absence, and/or the degree of filing of their ends, and/or the presence or the absence of the filter tip, by the aid of means being responsive to the stroke length of each feeler pin with respect to its support.
To perform, for example, the cigarette quantity testing, use is generally made of devices of the aforementioned kind, comprising a plurality of parallel feeler pins arranged in matching relation with the cigarettes of an orderly cigarette group, which is, for example, intended for making up a pack of cigarettes.
In the heretofore known devices, the feeler pins are mounted for an axially sliding movement within a feeler pin-carrying block, so as to project therefrom in the direction of the cigarettes, and are elastically urged toward the same by counter springs. In order to effect the testing, the whole feeler pin-carrying block is moved toward the cigarette group to be controlled so as to cause the feeler pins to be slightly pressed axially against the ends of the respective cigarettes. As the feeler pin runs into the matching cigarette, this pin moves axially back relatively to the feeler pin-carrying block, against the bias of the respective counter spring. The backward movement of the feeler pin is used as an indication of the presence of a cigarette. When a feeler pin does not run into a cigarette, it will not move back relatively to the feeler pin-carrying block, and its failure to move back is an indication of the absence of a cigarette.
To perform, for example, the cigarette quality testing, that is to say, the testing of the degree of filling of the cigarette ends, and/or of the presence of the filter tip, use is made of devices of the aforementioned kind, which are, for example, situated in correspondence of the hopper for feeding the cigarette-packing machines, and which comprise either one feeler pin, or two or more succeeding superposed feeler pins in matching relation with each duct for guiding the cigarettes down in said hopper. Also the operation of these known devices is the same as aforedescribed, and they comprise at least one feeler pin-carrying block, which is moved from a retracted rest position toward the cigarette or the cigarettes to be controlled, and in which the feeler pin or pins are elastically mounted so as to be axially slidable, and as to be backward movable.
The known testing devices of the aforementioned kind have several drawbacks, arising from the fact that upon every control, the feeler pin-carrying block is moved from a retracted rest position toward the cigarettes, and backward therefrom. In fact, in the first place, the movement of the whole feeler pin-carrying involves a complicated construction and needs cumbersome control devices, such as, for example, of the cam and lever type, to be provided. Moreover, particularly when the feeler pin-carrying block has a relevant mass and inertia, and/or when the cigarettes and cigarette groups to be tested follow each other at a very fast rate, it is also difficult and costly to synchronize the reciprocating movement of the feeler pin-carrying block with the sequential transition of the cigarettes to be tested in front of the said block. These problems arise, for example, when a device with a movable feeler pin-carrying block is used for the quality testing of cigarettes running down by steps through the cigarette-guiding ducts arranged side-by-side in the hopper for feeding a cigarette-packing machine. In fact, in this instance, the individual feeler pin-carrying blocks are each associated to one cigarette-guiding duct, and are joined the one to the other, so that they compose a feeler pin-carrying bar-like member extending across the entire width of the hopper. When considering that the number of the cigarette-guiding ducts arranged side-by-side in the feeding hopper of the packing machine may be equal to the number of the cigarettes contained in one pack, then the width of the hopper, and therefore the length of said bar-like member, may reach very large dimensions. Such a long bar-like member carrying the feeler pins has a considerable mass and consequently a considerable inertia, and must reciprocate at a very high rate, such as, for example, of 400 reciprocating motions per minute, so that its operation in synchronism with the downward running of the cigarettes through the cigarette-guiding ducts is very difficult, and requires cumbersome, complicated and costly driving means.
The invention aims to eliminate the aforementioned drawbacks of the known devices, and substantially resides in the fact that instead of causing the support of the feeler pin or pins to be moved toward the cigarettes and backward therefrom, control means are provided which let the feeler pin or pins free to move forward with respect to their support, under the bias of associated biasing springs, from a retracted rest position toward the matching cigarette or cigarettes to be tested, and which will retract subsequently the feeler pin or pins into their rest position within their support, against the bias of the respective biasing springs.
Thus, according to the invention, the block supporting the feeler pin or pins is kept stationary, and the feeler pin or pins are allowed, under the bias of the associated previously loaded biasing springs, to move from a retracted rest position in which they are held by suitable control means, toward the respective cigarettes to be tested and/or to be levelled. Any time a cigarette is present or is provided with the filter tip, and/or the degree of filling of a cigarette end is a regular one, the respective feeler pin is caused to move forward under the bias of the associated biasing spring, substantially only as far as to contact the cigarette, so that it stops after a relatively short, standard forward stroke. Whenever instead a cigarette is missing or is not provided with the filter tip, and/or whenever the degree of filling of a cigarette end is an unsufficient one, the corresponding feeler pin is caused to move forward under the bias of the associated biasing spring, over a longer than standard stroke, such as, for example, over the longest allowed stroke. In both instances, the differing length of the feeler pin forward stroke is used for such a testing. Once the testing has been effected, the control means will retract and hold the feeler pin or pins into their rest position, thus loading the respective biasing spring or springs.
The advantages attained by this invention appear evident from the foregoing. In fact, by contemplating only the movement of the feeler pin or pins, that have a mass and consequently an inertia which are considerably smaller than those of the block supporting same, the operation of the testing or levelling device synchronously with a very fast movement of the cigarettes to be tested or levelled, presents substantially smaller difficulties, and can be achieved with a remarkably simplified construction, and also with a reduction in the device overall dimensions.